I've collected 00 for years, but I recently dropped on an old 1950's Hornby tin plate engine in a charity shop, for a price I couldn't ignore. It brought back old memories of the engine that I'd inherited from my elder siblings many years before and my quest in oiling the motion, quartering the wheels and re-pinning the broken spring...

In Primary School, I used to fix other children's trains, which usually meant oiling them from a seized state, but on a few occasions, I was asked to remove the backs from tank engines to allow better access to the cabs and even loosen the tags holding the smoke box door in place to access the boiler inside, so no surprise to me that this engine was missing them and maybe karma!

What should I do, wait for a cheap body to turn up on eBay to cannibalise or design my own for 3d-printing???

Here's the results from my current project of restoration that I've extended to replace things like wagon wheels and even complete tenders....

I've put together a series of prints that I will slowly add to over time....

Some of the items that I've modelled, the Special Locomotive Wheels in particular, are based on internet photographs and maybe slightly off size: I appreciate any feedback on such details.

The tender project is based on a real 1949 vintage draughtsman plan, supposedly for B12, D16, J18, J19, J20 classes, uses a single filler cap rather than the later twin cap 3700 Gallon design by Thompson/Gresley. Yeadon's Register has it that the only B12 to use a 3450 Gallon Tender was number 8578, though both 3700 and 3450 Gallon variants are superficially identical.
Since I also wish to create a OO B12/3 Tender, I will yet produce a 3700 Gallon tender. Apologies for my changing of the file name yet again!
Cab doors modified 29/04/20

I've added new better scaled GER 12 spoke Wheels for my LNER style 3450 Gallon Tender and 10 spoke for the 3700 Gallon version:
GER 12 Spoked Tender Wheel.stl
GER 12 Spoked Tender Center Wheel.stl
LNER 10 Spoked Tender Wheel.stl
LNER 10 Spoked Tender Center Wheel.stl

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For a Complete Model Tender, you will need:

11.Hornby O Gauge Locomotive Tender
1 x LNER 3450 Gallon Tender.stl

08.Hornby O Gauge Locomotive Tender Wheels
3 x Axle Spacer.stl
4 x GER 12 Spoked Tender Wheel.stl
2 x GER 12 Spoked Tender Center Wheel.stl

12.Hornby O Gauge Tender Detail Kit
6 x Tender Axle Block.stl
1 x Tender Brake Handle.stl
1 x Tender Coal.stl
2 x Tender Loco Buffer.stl
2 x Engine Side Tender Buffer.stl
1 x Tender Step Front LH.stl
1 x Tender Step Front RH.stl
1 x Tender Step Rear LH.stl
1 x Tender Step Rear RH.stl

13.Hornby O Gauge Tender Spray Template
1 x Spray Template [your choice of style]
1 x Axle Cutting Gauge.stl

Plus 3 x 55mm length 2.5mm diameter steel axles (60 cut from 20 lengths of Stainless Steel 170x2.5mm Transmission Round Rod on eBay)

On more experience from building a prototype 3450 Gallon Tender from the original stl and with a view to making a 00 printable version (pictures to follow), I've now added a variant complete with steps front and rear, but kept the stepless version in place...